1. Transistor controls current.
2. Mosfet controls the Voltage.
1. Transistor amplifies current. For a small current you can gain large current (BETA). You can check this by varying the base resister. or the Forward beta settings. Also, if you swtich off the base current the circuit collapses.
2. Mosfet controls the voltage. It does not use gate current to continue to work. Once you start the FET using the gate switch the voltage flows through the bulb. It continues to work when you switch off the gate current.
